The old forum gave you a choice of going back to the forum or viewing your post after you posted in a thread. Am I missing something? Scrolling back throughout the whole thread to get back to the forum is tedious.

After you post something, you are automatically taken to that post. If you are in linear mode and on desktop view (not mobile), then you will see a scroll-to-top button at the bottom, which you can use to scroll back to the top.